In the previous article, we explored the visuable benefits of bilingualism in daily life. But where do these benefits originate? They are intricately linked to the brain development of bilingual individuals. Overall, it can be understood as follows: Bilinguals develop their brains by using two languages, which involves much more than simply memorizing vocabulary in both languages. It encompasses the monitoring, competition, and selection systems that are established to manage these two languages. These systems come into play every time a bilingual person speaks, a task that can be considered one of the most frequent brain activities. The practice of language selection and monitoring, executed implicitly and subtly in the mind, trains these systems so effectively that they can be applied/transferred in other aspects of life, even those unrelated to language.

As early as 1962, Peal et al. [4] from McGill University demonstrated that bilingual children may exhibit an advantage in mental flexibility, an idea stemming from the fact that bilinguals must easily switch between languages. This finding has since been confirmed and further endorsed by many recent researches through group comparisons, clinical experiments, and studies involving medical devices. For instance, Carlson and Meltzoff [5] from the University of Washington supported the notion that language experiences can influence the development of frontal lobe functions such as inhibition and attention control.

Quotes from academic and clinical experiments

Belows are some typical summary of how bilingual benefits on brain.

In the past two decades, there has been an upsurge of research investigating the consequences of
bilingualism for language processing, for cognition, and for the brain. This research demonstrates
a remarkable level of plasticity across the bilingual’s two languages, with evidence that the two
languages engage directly within a single language system that is stretched in different directions by
the conflicts and convergences present across each level of language use.[1]

This ability may be mediated by the frontal lobes and may
therefore exhibit a lifespan developmental trend that peaks in
young adulthood. The further suggestion is that the constant
necessity to exercise this inhibitory control leads to the
development of particularly effective attentional functions that
are then drawn on to mediate good performance on a variety of
nonverbal tasks requiring inhibition ofunwanted or misleading
material and concurrent selection of relevant aspects.[2]

Although it is certainly true that individuals may acquire expertise in a variety of skill domains, it is difficult to imagine a skill that is used more frequently than language. In this account, successful bilingual language processing is hypothesized to demand a very high level of skill in inhibitory control that then spills over from language itself to cognition more generally. [3]

Bilingualism appears to play a significant role in enhancing young children’s ability to ignore irrelevant information, reducing the competition that is imposed by cognitive conflict, and enabling an understanding of the arbitrariness of the way words are mapped to concepts.[3]

Performance on tasks that are purely cognitive, with little explicit linguistic content, is superior for older bilinguals than it is for older monolinguals.[3] note: This is relevant with the following point on alzheimer.

This experience provides continual practice in attentional control and results in its earlier development in children, improved functioning in adults, and slower
decline in older age. Therefore, bilingualism might contribute to cognitive reserve and protect older adults from decline in the context of dementia. This hypothesis was examined in the present study. [6]. note: this is based on clinical experiments on two groups of patients, which shows bilingualism can delay four to five years later in Alzheimer.

Thanks to the technology that delves into the intricacies of the human brain and our deeper understanding of neuroscience, more researches and medical applications finds the cognitive benefits of bilingualism at the neural level. These findings provide a strong base for the visible benefits we saw in our daily life.

Reference

[1] Kroll, J. F., Dussias, P. E., Bice, K., & Perrotti, L. (2015). Bilingualism, Mind, and Brain. In Annual Review of Linguistics

[2] Bialystok, E., Craik, F. I. M., Green, D. W., & Gollan, T. H. (2009). Bilingual minds. Psychological Science in the Public Interest

[3] Kroll, J. F. (2009). The consequences of bilingualism for the mind and the brain. In Psychological Science in the Public Interest

[4] Peal, E., & Lambert, W. (1962). The relation of bilingualism to intelligence. Psychological Monographs: General and Applied

[5] Carlson. (2014). Bilingual experience and executive functioning in young children. developmental science

[6] Bialystok, E., Craik, F. I. M., & Freedman, M. (2007). Bilingualism as a protection against the onset of symptoms of dementia. Neuropsychologia